Drunk-driving conviction overturned due to unexplained connection

The Appeals Court has reversed a man’s convictions for drunk driving and causing serious bodily injury due to the prosecution’s “deficient” evidence.

The commonwealth introduced a toxicologist expert witness at trial but never had him explain to the jury the “fundamental connection between the amounts of [the defendant’s] blood alcohol content and the punishable condition of impairment: the diminished capacity to operate a motor vehicle safely.”

Because of the omission of an explanatory connection, the Appeals Court found, the jury was improperly left “to guess at the meaning of the breathalyzer measurements.”